Improvement in monochord tuning-instruments



UNITED STATES PATENT OEErcEo ERASTS D. BOOTMAN, OF EAMESTON, NEWT YORK.

IMPROVEMENT lN MONOCHORD TUNING-lNSTRUMENTS.

Specification forming` part of Letters Patent No. 40,012, dated September 22, 1863.

To all whom t may concern.-

Be it known that I, Ennsrus D. BoorMAN, of Earneston, in the county of Otsego and State of New York, have invented a new and Improved Monochord Tuning-Instrument for Timing Pianofortes and other Musical Instruments 5 and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specitication, in which- Figure l is a plan of a tuning-instrument constructed according to my invention. Fig. 2 is a transverse vertical section ot the same. Fig. 3 is a face view of the two pieces which constitute the movable stop or bearing of the string.

Similar letters of reference indicate corre spending parts in the several figures.

The principal object ot this instrument is to enable those who play the piano-forte to tune their own instruments. It is composed of a l single string or monochord arranged over a sound-board in a suitable case, and a bridge, bearing, or stop, which is movable upon the sound-board to stop the string at the point to make it produce a required note.

The improvement consists in a very simple and effective construction of the said movable bridge, bearing, or stop, and mode of applying the same to the sound-board.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

G is the case of the instrument, consisting, of a light wooden box, which may be of about two feet in length and of any suitable width and depth, and having secured within its upper part the sound-board H, under or at the ends of which there is suitable blocking for the reception of the pins a b, which secure the ends of the string I. a is a tuning-pin, applied like the tuning-pins of piano-fortes or other stringed instruments, and b is a pin or screw of any kind that will secure the string. c and d are two fixed bridges near the pins a b, forming permanent bearings for the string.

J and K are two pieces of steel or other metal, which constitute the movable bridge, bearing, or stop, to stop the string at tne point to make it produce a required note. 'Ihese pieces are flat and of a thickness to lit snugly into any one of a series ot' small transi l verse mortises, e e, provided in the soundl board under the string for their reception. l The piece J, which is inserted in the mtrtise behind the string, is made with a shoulder,f, to give it a bearing upon the soundboard and prevent it from slipping too far through the mortises therein, and it is provided in tbe edge which comes next the string with a notch, g, which is so arranged that the strings may enter it when the shoulder f comes to a bearing on the sound-board. The other piece, K, which is inserted in frontofthe string into the same mortise with J, is of wedge shape, and when inserted it is pushed in until by its wedge-like action against the front end ot' the mortise it is caused to clamp the string against J. The two pieces are beveled on one side, as shown at h in Fig. 3, to make those parts of their edges between which the string is clamped very thin. rIhe movable bridge, bearing, or stop, thus constructed is very simple and easily adjusted, l costs very little, and makes a very effective bearing for the string supporting it both in a i lateral and a vertical direction.

The proper positions for the mortises e e are found by the mathematical division of the l string in suchmanner as to make all the in- 5 tervals of the chromatic scale equal, thereby producing a perfect equal temperament. I prefer to have the string of such size and length that when open-that is to say, when the stop J K is taken away and it rests only upon the bearings c and d, it will give the note of the middle D of the piano-forte, and to have the scale on the monochord represented by the mortises e e extend two octaves above this D. The several mortises are lettered D Di, E, &c., to indicate what note the string will produce when stopped opposite to either of them.

Before timing' a piano-forte the open string I is timed by the aid or" a tuning-fork or by other means. When this has been done, the middle Dstring of the piano is to be tuned in unison with I. The stop J K is then placed in the mortise to make D octave above and the corresponding D-string ot' the piano tuned, and the two D-strings compared to ascertain if correct. The stop is next taken out and put in the tirst mortise from the bridge d to make DQ, and the corresponding string of the piano tuned to it, and the stop is then removed to the mortise representing; the D?, oe VVhnt I claim as my invention, and desire to t bve above, and the piano-string eorrespond- 1 secure by Letters Patent, is-

izig with that is tuned and compared WithD The movable bridge, bearing, or stop, oombelow. The stop is next removed back to E, posed of two pieces of steel or other metal, and the piano tuned to correspond, after which J K, as described, in combination with the the stop is moved to E to tune the octave mortises e e in the sound-board, substantially above, and this shiftingof the stop and tuning;1 as and for the purpose herein set forth.

are continued throughout the tivo oetaves of ERASTUS D. BOOTMAN. the selle of the monoehord. The remaining Witnesses:

0 :reves of the piano are tuned from the two DAVID B. ST. JOHN,

which are tuned from the monoehord. i TRUMAN BOO'IMAN. 

